Scrapers are used in pipelines, particularly for water, oil or gas transportation, for discovering faults in the pipeline, for cleaning pipelines and the like. These functions are essentially taken over by components located on the outer circumference on support parts, such as sensors for inspecting the state of the pipeline wall. There is a clearly definable spacing between the components and the inner wall or outer wall in the case of different cross-sectional robot sizes. The components are fixed to radially expandable support elements, which succeed one another in the circumferential direction of the pipeline.
In order to be able to use such scrapers in pipelines with different standard widths, such as 26 and 42 inches, or to be able to inject the scrapers via supply lines into the pipeline, test scrapers with radially expandable support structures located on a central pulling part are known and on the circumference thereof are located sensors. Such support structures with a circumference variable as a function of the internal cross-section of the pipeline have several substantially radially arranged support arms pivotable about axes perpendicular to the longitudinal median axis of the pulling part (DE 197 46 510 A1, DE 197 46 511 A1).
It is also known from DE 197 46 511 A1 for the positioning of sensors in circumferentially displaced manner on in each case two support frames which are movable axially against one another and which in the case of a given pipe circumference can be moved into one another in such a way that the sensors cover the entire pipeline circumference. The sensors are not uniformly distributed, because the spacings between the two support frames vary. This construction is relatively complicated and leads to high production costs, because for each different pipe diameter in each case a different support frame is required. It is also desirable to have a greater measurement resolution in the circumferential direction of the pipeline and for this purpose a larger number of sensors relative to the pipe diameter is necessary.
DE 102 10 746 C1 describes a sensor support body of a scraper, in which the individual segments are joined together in the circumferential direction of the pipeline to form a hollow body with a cylindrical surface, the segments in the axial direction comprising at least two successive skid pairs, which are elastically interconnected by connecting elements in order to bring about a high arc traversability of the scraper. EP 255 619 B1 and DE 203 06 958 U1 disclose a sensor support in the form of a sleeve with rubber-like characteristics, which can adapt to the pipe wall and in particular to pipeline unevennesses. These arrangements lead to higher operational and functional reliability of the scraper, but are only suitable for testing pipelines having a standard width. For different pipe diameters different constructions are necessary, which leads to high manufacturing costs and to a considerable storage expenditure.
The problem of the invention is to provide a device of the aforementioned type which, whilst avoiding the aforementioned disadvantages, can be more particularly used in pipelines having different standard widths and has a high operationally reliability, a higher measurement resolution in the circumferential direction and a simple, inexpensive construction.